The IS-2 was the first of the Iosif Stalin series of heavy tanks to enter mass production and became the most important Soviet heavy tank of the final two years of the war. Development of the IS-2 was prompted by fitting of an 85mm gun on the T-34; this made it necessary for a heavy tank to carry even larger armament, in this case a massive 122mm A-19 gun (and later D-25T) that was the highest caliber weapon fitted on a World War II tank. Despite the gun's size, it was never meant primarily as a tank-killer and in fact its penetration power was slightly weaker than that of the German Panther. Still, the IS-2 benefited from impressive armor protection which reached 132mm maximum and that was modified throughout its production run to feature a prominent slope on the front glacis. A more compact component design also enabled it to remain smaller than comparable German heavy tanks, and consequently lighter as well. However, the IS-2 suffered from very low ammunition storage capacity as well as a slow rate of fire of just 2-3 rounds per minute, although this was partially remedied by switching to the more efficient D-25T gun. Despite these drawbacks, the IS-2 was an invaluable asset to the Red Army's late-war offensives after its introduction in early 1944, where it was used primarily for infantry support but as a tank-killer whenever necessary. It's most memorable action was during the Battle of Berlin where it proved excellent for urban combat on account of its gun, protection as well as powerful secondary armament; it was also during this battle that it gained its nickname of 'Victory tank'. The IS-2 remained in Red Army until the 1950s as well as in the armies of China, Cuba and North Korea but did not see further action as they were gradually replaced by the IS-3 and T-55.

The IS-2 was a linear development from the short-lived KV-85 and IS-1 tanks. The IS-2 shared the same hull and turret as the IS-2 but with the addition of a more powerful gun; initially a 100mm on a prototype known as the IS-100 and later the 122mm A-19 gun that was standard on initial vehicles. The IS-2 (mod 1944), also known as the IS-2M was a modified version introduced later in 1944 that eliminated the stepped front for a fully sloped glacis plate and also the improved D-25T gun. Further minor modifications were carried out post-war.